Hello T
Welcome to Poms in Oz.
There is no upper age limit on the temporary, employer-sponsored subclass 457 visa.
The ENS and RSMS visas both confer Permanent Residence in Australia from Day One and although the starting point is that the applicant should be under 45, age-exemptions are potentially available with both visas depending on your occupation. Please see the following links:
Employer Sponsored Workers - Workers - Visas & Immigration
Information Booklets - Applications & Forms - Visas & Immigration
Employer Nomination Scheme (Subclass 121/856)
Regional Sponsored Migration Scheme (Subclass 119/857)
What is your occupation, please?
Also, if you and your Partner are in a long term relationship only one of you needs the skilled visa. The other can be included as his/her Partner and the Partner can do whatever job s/he wishes after arrival in Oz.
Your own idea seems to be verging on thinking about a possible student visa. I suspect that that may not be necessary.
What does your Partner do, please?
Best wishes
Gill